JPS63273071A - Temperature rise tester for large current bushing - Google Patents

Abstract

PURPOSE:To reduce the number of power supply current transformers for utility by constituting an instrument such that the power supply current transformers and measuring current transformers are electromagnetically coupled with a plurality of air conductors and the sum of currents flowing in the air conductors flows in a large current bushing. CONSTITUTION:Power supply current transformers 21 and 22 and also measuring current transformers 23 and 24 are electromagnetically coupled with air conductors 17 and 18, respectively. Currents are induced in the conductors 17 and 18 by the current transformers 21 and 22 from an AC power supply 27 via an induction voltage regulator 26. Thus, the temperatures of the various portions of a large current bushing 3 are measured and its quality is judged. Since the conductors 17 and 18 are connected in parallel between the terminal plates 6a of the air terminal metals 6 of the bushing 3 and a leader bushing 16 and the current transformers 21 and 22 are arranged on the conductors 17 and 18, respectively, the impedances of the conductors 17 and 18 are reduced and the value of current confluent in the bushing 3 can be increased. Therefore, the number of the power supply current transformers for utility can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a temperature rise test device for large current bushings of 300 A or more.

(Prior art) Generally, the temperature rise test device for large current bushings is
As shown in the figure, a large current bushing 3 and a drawer bushing 16 are attached to an oil tank device that simulates a transformer, with an oil tank 1 filled with insulating oil 0. These are connected by a stranded wire 31 (hereinafter simply referred to as an air conductor 3I), and the submerged terminal fittings of both bushings 3.16 are connected by a conductor 32 to form a closed circuit.

On the other hand, the induced voltage regulator 26 is connected to the 200cm AC power supply 27.
A plurality of power supply current transformers 33 are connected in parallel through the transformers 33 and electromagnetically coupled so that the aforementioned closed circuit becomes a one-turn secondary winding. Furthermore, the number of power supply current transformers 33 in parallel is increased and the size of the conductor 31 is determined depending on the current value to be applied to the large current bushing 3. The current flowing through the secondary winding is measured by a measuring current transformer 34 and an ammeter 35. Note that 26 is an induced voltage regulator connected to the power supply current transformer 33, and 27 is an AC power source.

(Problem to be Solved by the Invention) However, the conventional bushing test device described above
When the current density exceeds a certain value due to the skin effect, the conductor impedance increases, and even if the number of power supply current transformers 33 is increased, there is a problem that the current value does not increase accordingly. Furthermore, when a plurality of power supply current transformers 33 are arranged in a row, the minimum width required for arrangement increases, and the air conductor 31 forming the aforementioned closed circuit has to be enlarged. As a result, the impedance of the secondary winding (air conductor 31) formed in a closed circuit increases, and if the number of power supply current transformers 33 is constant, the current flowing through the secondary winding, that is, a large There was a problem in that the current flowing through the current bushing 3 became small.

SUMMARY OF THE INVENTION An object of the present invention is to provide a test device for a large current bushing that is capable of passing a predetermined current through a large current bushing under test using as few power supply current transformers as possible.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides penetrating support for the lead-in bushing and the test high-current bushing in an oil tank, and connects the terminal fittings on the oil-submerged side of both bushings. The terminal fittings on the air side are connected in parallel by multiple air conductors, and a power supply current transformer and a measurement current transformer are electromagnetically coupled to each air conductor. measures are being taken.

(Function) In order to form a plurality of closed circuits with a plurality of aerial conductors, the present invention increases the amount of conductive material such as copper used to form the aerial conductors, lowers the impedance of the closed circuit, and transforms the current for power supply. The number of devices used can be reduced, and a large current can be passed through the air conductor.

(Example) Hereinafter, an example embodying the present invention will be described based on FIGS. 1 to 3.

A large current bushing 3 is supported so as to penetrate through a gasket 2 on the upper surface 1a of an oil tank l for storing test insulating oil of the large current bushing 3 under test.
A flange fitting 4 provided in the middle is fixed to the upper surface 1a with bolts (not shown). Further, a conductive cylinder 5 made of copper with oil passages 5a-t transparent therethrough is inserted into the inner cavity 3a of the large current bushing 3, and a terminal plate 6a is attached to a male screw 5b formed at the upper end thereof. An air terminal fitting 6 is screwed together. Further, a cover plate 7 is fixed to the upper end of the conductive cylinder 5 by a metal fixing Wq8 such as wax or baked silver.
A gasket 9 is interposed between the cover plate 7 and the upper end surface of the high current bushing 3 to maintain oil tightness.

On the other hand, an oil-immersed terminal plate 11 is provided on the inner periphery of the lower end of the conductive cylinder 5.
The oil-submerged terminal fitting 10 with the attached terminal fitting 10 is fitted and fixed, and a tightening ring 15 is screwed onto the outer peripheral male screw 10a of the terminal fitting 10, and between the tightening ring 15 and the lower end surface of the high current bushing 3. A spacer 12, a spring 13, and a seat plate 14 are fastened and fixed to the.

Further, the high current bushing 3 is provided on the upper surface 1a of the oil tank 1.
Similarly, a drawer bushing 16 is fitted. And the terminal plate 6a on the air side of both bushings 3.16
, 6a, as shown in FIG. (referred to as a second air conductor 18) are connected in parallel. In addition, in the oil tank 1, the oil-submerged terminal fittings lO of both bushings 3 and 16 are
An oil-submerged flat copper plate or copper stranded wire 19 (hereinafter simply referred to as oil-submerged conductor 19) is connected between the oil-submerged terminal plates 11 and 11.

The first and second aerial conductors 17.18 have a height of 1 m.
A first power supply current transformer 21 and a second power supply current transformer 21 supported on a frame 20 of
The power supply current transformers 22 are electromagnetically coupled, and
The first measuring current transformer 23 and the second measuring current transformer 24 are also electromagnetically coupled. Said re-measuring current transformer 23.24
An ammeter 25 is connected to each. Further, the dual power supply current transformers 21 and 22 are connected to a 200cm AC power supply 27 via an induced voltage regulator 26.

On the other hand, an oil circulation path 28 is connected to the oil tank 1 in order to circulate the insulating oil 0 and heat it to an appropriate temperature, and an oil pump 29 and a heating device 30 are connected in series along the way.

Next, the operation of the high current bushing temperature rise test device configured as described above will be explained.

“In this temperature rise test equipment, high current bushing 3
Thermocouples (paths shown) are installed at the required locations, and each thermocouple is connected to a temperature measuring device.

Now, the oil pump 29 and the heating device 30 are operated to maintain the temperature of the insulating oil O in the oil tank 1 at a reference temperature (for example, 40° C.).

On the other hand, a current is induced from the AC power supply 27 through the induced voltage regulator 26 and the first and second power supply current transformers 21 and 22 in the first air conductor 17 and the second air conductor 18 .

In this way, the quality of the bushing 3 is determined by measuring the temperature generated in each part of the large current bushing 3.

Now, in the embodiment of the present invention, the large current bushing 3 and the drawer bushing 160 are connected to the terminal plate 5a of the air terminal fitting 6°6.
, 6a, the first air conductor 17 and the second air conductor 18 are connected in parallel, and the first power supply current transformer 21 and the second power supply current transformer 22 are connected to both the air conductor cables 17 and 18. Since I placed
By reducing the impedance of the solid air conductive cables 17, 18, the current value flowing into the high current bushing 3 can be increased. Furthermore, compared to conventional test equipment in which a large number of power supply current transformers are electromagnetically coupled in series to one long cable, the margin of installation space can be increased.

Bushings that connect the atmosphere to the atmosphere, such as through-the-wall bushings at substations, have higher voltage classes, such as 275KV.
, 4000A through-wall bushing, the length of the bushing is 11 m, and in the conventional method, 10 current transformers for power supply had to be connected in parallel. However, in the method according to the present invention, a total of 8
The predetermined current is 40 at the power supply current transformer 21 and 22.
00A could be applied to the bushing.

In the above embodiment, the current transformers 21 and 22 for dual power supplies were floated approximately 1 m above the ground using the pedestal 20, but in this case, the floating magnetic flux is reduced, so the high current bushing 3
It is possible to further increase the current flowing through the current.

Effects of the Invention As detailed above, the present invention electromagnetically couples a power supply current transformer and a measuring current transformer to a plurality of air conductive cables, and a large current bushing that connects a plurality of air conductive cables to each other, and has a large current bushing that is connected to the current flowing through each air conductive cable. Since the total current of There is.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a road body showing an embodiment of the electrical testing device for bushings of the present invention, Fig. 2 is a front view showing the support structure of a power supply current transformer, and Fig. 3 is a front view of the entire testing device. , FIG. 4 is a road body circuit diagram showing a conventional temperature rise test device for large current bushings. DESCRIPTION OF SYMBOLS 1... Oil tank, 3... Large current bushing, 5... Conductive cylinder, 6... Air terminal fitting, 10... Oil submerged terminal fitting, 11... Oil submerged terminal plate, 16 ... Drawer bushing, 17... First air conductor, 18... Second air conductor, 19... Oil submerged conductor, 20... Frame, 21...
Current transformer for first power supply, 22... Current transformer for second power supply, 23
. . . 1st measurement current transformer, 24 . . . 2nd measurement current transformer.

Claims (1)

[Claims] 1. A retractable bushing and a high-current test bushing are supported through the oil tank, and the terminal fittings on the oil side of both bushings are connected to each other by a conductor, and the terminal fittings on the air side are connected to each other by a plurality of A temperature rise test device for large current bushings, which is connected in parallel by air conductors, and each air conductor is electromagnetically coupled to a power supply current transformer and a measurement current transformer. 2. The temperature rise test device for large current bushings according to claim 1, wherein the power source and measuring current transformers are installed on a pedestal with a height of 1 m.